Selective travel draft gear arrangement



April 12, 1966 E. H. NA-rscHKE SELECTIVE TRAVEL DRAFT GEAR ARRANGEMENTFiled June 22, 1964 2 Sheets-Sheet 1 MW @NN x lull I NNE h\ April 12,1966 E. H. NATscHKE SELECTIVE TRAVEL DRAFT GEAR ARRANGEMENT Filed June22, 1964 2 Sheets-Sheet 2 6m Y a l Wam/W y? @55 5.

United States Patent O 3,245,552 SELECTIVE TRAVEL DRAFT GEAR ARRANGEMENTEldred H. Natschlte, Bourbonnais, Ill., assigner to CardwellWestinghouse Company, a corporation of Delaware Filed June 22, 1964,Ser. No. 376,767 5 Claims. (Cl. 213-46) This invention relates toselective travel draft gear arrangements for application to the draftpocket of a railroad car frame, and has for its principal object theprovision of a draft gear arrangement that incorporates a hydraulic uidthrottling type cushioning unit that is operable only in buff, and apositive resistance type of spring cushioning unit that is operableduring both buff and draft, with the combined travel of the two units inbuiiE being several times greater than the travel of the positiveresistance unit in draft.

The dydraulic units have important features that are highly desirablefor draft gear application, such as offering high capacity and offeringincreasing resistance and energy absorption at the higher impact speeds.Hydraulic units also have a number -of disadvantages which limit theirdesirability for draft gear applications. One ditiiculty with hydraulicunits arises from the fact that they can be operated through their fullrange of travel in response to a light force constantly applied. Draftloads of this nature are frequently encountered during train operation,and objectionable train run-in and run-out can result when tthehydraulic units are applied for handling draft loads.

Accordingly, another object of the invention is to provide a draft geararrangement incorporating a hydraulic -cushioning unit that is operableonly under buff loading.

Another disadvantage of hydraulic units arises yfrom the fact that thehydraulic unit undergoes some delay immediately `following impact beforeeffective cushioning action is developed. For this reason, hydraulicunits at the yshorter ranges of travel, on the order of 3 inches, havean unduly large travel portion that is ineffective.

Accordingly, another object of the invention is to provide anarrangement wherein the hydraulic unit may operate over a substantiallygreater travel range to enable a higher percentage of its closure stroketo offer effective cushioning action.

Generally speaking, the draft gear arrangement of this inventionincludes a housing located in a draft pocket defined outwardly of thebolster center filler, with the housing projecting beyond the car frameand serving as a movable carrier for the usual coupler which must bespaced a distance great enough to accommodate the required travel.

In accordance with this invention, the housing mounts a hydraulic typecushioning unit within a chamber at its rear end and a positiveresistance type cushioning unit within a chamber at its front end. Animportant feature of the arrangement resides in the fact that theselective travel characteristics and the greatly increased buff travelas compared with draft travel, are achieved without requiringsubstantial modification of the center sills.

Accordingly, a further object of the invention is the provision of aselective travel draft gear arrangement for use in a car having abasically standard center sill construction and wherein a hydraulic typecushioning unit functions only in buff to provide a buff travel severaltimes greater than the draft travel which is afforded by a positiveresistance unit that also is operable in buff.

Other and further objects of the present invention will be apparent fromthe following description and claims, and are illustrated in theaccompanying drawings which show structure embodying preferred featuresof the present invention and the principles thereof and what is nowconsidered to be the best mode in which to apply these principles.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame:

FIG, 1 is a horizontal section through familiar parts of a freight carunderframe showing the draft gear arrangement applied in the draftpocket;

FIG. 2 is a vertical section of the same;

FIG. 3 is a transverse section taken as indicated on the line 3 3 ofFIG. l; and

FIG. 4 is a fragmentary side elevational view of the end region of acenter sill and is taken as indicated by the 4 4 of FIG. 3.

Referring now to the drawings, .the selective travel draft geararrangement of this invention is disclosed as applied in a conventionalrailway car underframe that includes lengthwise extending -lixed centersills 10, a bolster center filler structure 11, mounted between thesills in the usual v fashion and having rigid stops in the form ofintegral extensions IilS bordering and defining rear lateral extremitiesof a draft pocket P that extends from the location of the stops 11S tothe end of the car frame. A coupler 12 is illustrated projecting intoIand movable lengthwise in the pocket to apply buff and draft loads.

The draft gear arrangement of this division is designated generally aty13 and it is mounted in the pocket to undergo selective closure travelfor developing cushioning of butt and draft loads. The draft geararrangement includes a housing `14 having a top wall 15, a bottom Wall16, and side walls 17 and including a lfixed transverse abutment wall 1Sthat defines separate front and rea-r chambers 19 and 20 in the housing.The wall 18 is approximately lcentrally located along the housing, withthe front chamber 19 being only slightly longer than the rear chamber2i). f

The housing -14 has its front end projecting forwardly from the draftpocket P defined by the center sills 10 and has its rear end extendingdeep into the pocket and terminating in forwardly spaced facing relationto the stops 11S to accommodate movement of the housing towards thestops 11S under buff loads. The front cham-ber 19 of the housing is openforwardly and defines .a space large enough to receive the shank 12S ofthe coupler. The rear chamber of the hou-sing opens rearwardly towardsthe bolster center filler structure 111.

A cushioning unit 21 is mounted in the front chamber 19 to react betweenthe intermediate abutment wall 18 and the butt end of the coupler shank12S and a cushioning unit 22 is mounted in the rear chamber 2 andextends rearwardly therebeyond to react between the abutment wall andthe rear stops =11S. A rear follower 23 is located immediately forwardlyof the rear stops to transmit reaction between the rear cushioning unit22 and the rear stops.

Adjacent the front end -of the housing 14 its side walls `17 areprovided with a central set of aligned slots 24 (sometimes hereinafterreferred to as a second set of slots) and upper and lower sets ofaligned slots 25 and 26 respectively, (sometimes hereinafter referred to-as a first set of slots) `flanking the center set and spaced rearwardlyalong the housing walls to overlap only partially with the center set ofslots `24, The coupler 12 has the usual horizontal slot 27 to receive -ahorizontal draft key 28, the ends of which project through the centerset of slots 24 in the housing and through open ended slots 29 providedin the center sills for transverse alignment with the center set ofhousing slots 24. An upper stop key 30 is located above the couplershank 12S and extends through the upper set of housing slot 25 andthrough a corresponding upper set of closed-end center sill slots 31.Similarly, a lower stop key 32 underlies the coupler shank 12S andextends through the lower set of housing slots 25 and through a lowerset of closed-end center sill slots 33.

The cushioning unit 21 in the front chamber of the housing is preferablyin the form of an aligned stack of rubber mats mounted as a boltedassembly within the housingT '14. For this purpose a front follower 34is located at -the front of the unit 21 `to abut the coupler shank andis slidable relative to bolts 35 which are anchored in countersunkrelation in the intermediate abutment wall 18 -that functions as anintermediate follower operating between the two cushioning units 21 and22. One type of rubber mat draft gear arrangement that may be utilizedin the front chamber 19 is shown in Tucker Patent No. 2,705,569.Alternative arrangements contemplated for use in the front chamber areshown in Peterson Patent No. 3,025,974, in which case `the walls of thehousing would be provided with appropriate cut-outs to accommodatelocking facilities.

Since the cushioning unit 22 utilized in the rear chamber 2t) is a`fluid throttling type of hydraulic mechanism, it is desirable that arubber draft gear unit be employed in the front chamber, but theinvention need not be thus limited as it is contemplated -that thecushioning unit 21 in the front chamber might alternatively be in theform of coil springs or a combination of rubber and coil springs andmight, in addition, include a friction clutch mechanism. All such typesof cushioning units are prescribed herein under the phrase a positiveresistance type of cushioning unit, and it will be apparent that each ofthese is also self-restoring in that it returns to its initial -releaseconfiguration upon removal of the load.

In the preferred practice of the invention, the hydraulic cushioningunit for the rear chamber may be of the type shown in co-pendingapplication of Campbell and Natschke, Serial No. 278,952, filed May 8,1963. The principal components of this hydraulic cushioning unit areillustrated herein and include a cylinder 36 fixed within the rearchamber in abutting relation to `the in- -termediate abutment wall 18, apiston 37 slidably operable in the cylinder, a piston rod 38 projectingthrough the rear of the cylinder and connecting to the rear follower, anend cap 39 at the rear of the cylinder, and a rubberlike bellowsdiaphragm 40 sealed to the rod 33 and to the end cap 39 for preventingleakage of hydraulic fluid from the low pressure side of the hydraulicsystem. The particular hydraulic unit has its piston 37 equipped with anautomatically variable orifice arrangement responsive to pressureconditions to vary the orice size, and lthe details of its constructionand action are fully disclosed in the aforesaid Campbell and Natschkeapplication, and are specifically incorporated herein by reference.

While a particular hydraulic unit is referred to herein, the inventioncontemplates the use of other hydraulic arrangements, particularly thosewhich produce a constant reaction force throughout their travel range.It should also be apparent that the relationship of the piston rod tothe cylinder may be reversed, in that the piston rod may be adjacent andconnected to the intermediate abutment wall, and the cylinder may beexternal of the rear chamber of the housing and connected to the rearfollower.

The parts of the draft gear arrangement are shown in their releaseposition in FIGS. l and 2. The hydraulic cushioning unit includes alarge coil return spring 41 which encircles the cylinder 36 and pistonrod 38 and reacts against the rear follower 23, to cause ythe :housing13 to be urged forwardly to hold the stop keys 30 and 32 against theforward ends of the center sill slots 31 and 35, thus presenting apositive stop against which `the front follower 34 of the frontcushioning unit 21 may react.

Under draft loads, the coupler 12 moves forwardly and acts through thedraft 4key 28 to draw the housing 14 forwardly, causing yitsintermediate abutment wall 18 to move in compressing relation towardsthe now stationary i front follower 34. The cushioning unit 21 in thefront chamber 19 may have a closure -travel on the order of l inch, ormore, if desired, but it is usually unnecessary to provide more than twoinches of -travel for this unit.

Under buff loads, the coupler shank 12 moves rearwardly to transmitforces serially through the front follower 34, through the frontcushioning unit 21, through the intermediate abutment wall 18, andthrough the hydraulic cushioning unit 22 and rear follower 23 and theninto the stops 11S. The rear cushioning unit 22 undergoes a closureequal to the Itravel clearance :of the housing 14 relative to the rearfollower 23 as indicated at T in FiG. 2. Ultimately the housing 14 goessolid through the follower 23 and the rear stops 11S to limit pressurebuilt-up in the hydraulic cushioning unit, but at this time the rubbercushioning unit 21 is still active. In its release position the rear ofthe housing is spaced nine inches forwardly of the rear follower 23 toprovide a nine-inch closure travel for the hydraulic cushioning unit.

Thus, the arrangement affords a hydraulic cushioning unit travel (9inches) that is several times greater than the rubber cushioning unittravel (l inch) under buff loads. Moreover, the hydraulic unit issubjected to a closure speed closely approaching the coupler speed andthis insures higher eiiiciency cushioning as the hydraulic unit `is moreeffective at higher closure speeds. The reserve capacity of the rubberunit 21 protects against excessive impact loads while satisfying allrequirements for cushioning of draft loads.

At their outer ends, the sills 10 are equipped with cheek plates 42 and43 bordering the slots 29, 31, and 33 to reinforce -the structureagainst which the stop keys 39 and 32 react. Outboard shields 44 and 45are applied to the cheek plates after insertion of the stop keys toretain the keys against accidental escape.

Thus, while preferred constructional features of the invention areembodied in lthe structure illustrated herein, it is to be understoodthat changes and variations may be made by those skilled in the artwithout departing from the spirit and scope of the appended claims.

What yis claimed is:

1. In combination with car underframe structure that includes lengthwiseextending fixed sills defining a draft pocket, a coupler projecting intoand movable lengthwise in said pocket, a bolster center vfiller betweensaid sills and -having rigid stops bordering and defining rear lateralextremities of said pocket, a selective travel draft gear combina-tioncomprising a housing projecting forwardly from said sills and extendinglengthwise rearwardly into said pocket to terminate in forwardly spacedfacing relation to said stops to move towards said stops in buff, saidhousing having a rear chamber opening t0- wards said center filler, afront chamber opening endwise oppositely of said rear chamber and rigidinternal abutment wall structure dividing said chambers, a follower linsaid pocket to abut said rear stops, a cushioning unit mounted in saidrear chamber to operate only in buff and including means projectingrearwardly therefrom and engaged to said follower to transmit buffreaction to said stops, said cushioning unit being a self restoringhydraulic uid throttling type and having a Coil type return springencircling said means and reacting between said follower and saidintermediate abutment wall structure, a positive resistance typecushioning unit mounted within said front chamber between said couplerand said intermediate abutment wall structure, to operate in both buffand draft, said housing and said sills having first and second sets ofslots aligned transversely of said pocket, transverse stop key meansprojecting through said sets of slots and connecting said housing forlimited lengthwise movement relative to saidr sills, said housing andcoupler having slots aligned transversely of said pocket, and transversedraft key means projecting into the last named slots and connecting saidcoupler and housing.

2. In combination with car underframe structure that includes lengthwiseextending fixed sills Adefining a draft pocket, a coupler projectinginto and movable lengthwise in said pocket, a bolster center fillerbetween said sills and having rigid stops bordering and defining rearlateral extremities of said pocket, a selective travel draft gearcombination comprising a housing projecting forwardly from said sillsand extending lengthwise rearwardly into said pocket to terminate inforwardly spaced facing relati-on to said stops to move towards saidstops in buff, said housing having a rear chamber opening towards saidcenter filler, a front chamber opening endwise 0ppositely of said rearchamber and rigid internal abutment wall structure dividing saidchambers, said housing and said sills having first and second sets ofslots aligned transversely of said pocket, transverse stop key meansprojecting through said sets of slots and connecting said housing forli-mited lengthwise movement relative to said sills, said housing andcoupler having slots aligned transversely of said pocket, transversedraft key means projecting into the last named slots and connecting saidcoupler and housing, a cushioning unit comprised of an aligned stack ofrubber pads mounted within said front chamber yto react in buff betweensaid coupler and said intermediate abutment wall structure and to reactin draft between said stop key means and said intermediate abutment wallstructure, a follow in said pocket to abut said rear stops, and acushioning unit mounted in said rear chamber and including meansprojecting rearwardly therefrom and engaged t-o said follower totransmit buff reaction to said stops, said cushioning -unit being aselfrestoring hydraulic fluid throttling type and having a coil typereturn spring encircling said means and reacting between said followerand said intermediate wall structure to establish a release position forthe draft gear combination wherein said housing is biased forwardly tohold the first named cushioning unit against said stop key means andprovide clearance for rearward housing travel to enable a closure travelof the second named cushioning unit in buff in an amount several timesgreater than closure travel of the first named cushioning unit in draft.

3. In combination with car underframe struct-ure that includeslengthwise extending fixed sills dening a draft pocket, a couplerprojecting into and movable lengthwise in said pocket, a bolster centerfiller between said sills and having rigid stops bordering and definingrear lateral extremities of said pocket, a selective travel draft gearcombination comprising a housing projecting forwardly from said sillsand extending lengthwise rearwardly into said pocket to terminate inforwardly spaced facing relation to said stops to move towards saidstops in buff, said housing having a rear chamber opening towards saidcenter filler, a front chamber opening endwise oppositely of said rearchamber and rigid internal abutment Wall structure dividing saidchambers, said housing and said sills each having finst and second setsof slots at anking locations above and below said coupler and alignedtransversely of said pocket, transverse stop keys means projectingthrough said sets of slots and connecting said housing for limitedlengthwise movement relative to said sills, said housing and couplerhaving slots aligned transversely of said pocket, transverse draft keymeans projecting into the last named slots and connecting said couplerand housing, a positive resistance type cushioning unit mounted withinsaid front chamber to react in buff between said coupler and saidintermediate abutment wall structure and to react in draft between saidstop key means and said intermediate abutment wall structure, and acushioning unit mounted in said rear chamber and including meansprojecting rearwardly therefrom and connected to transmit buff reactionto said stops, said cushioning unit being a self restoring hydraulicfluid throttling type and having a coil 6 type return spring encirclingsaid means and reacting between said stops and said intermediate wallstructure to establish a release position for the draft gear combinationwherein said housing is biased forwardly to hold the first namedcushioning unit against said stop key means and provide clearance forrearward housing travel to enable a closure travel of the second namedcushioning unit in buff in an amount several times greater than closuretravel of the first named cushioning unit in draft.

4. In a railway car underframe of the type having fixed center sillscarrying fixed stops defining rear lateral extremities of a draft pocketthat opens endwise forwardly from said sil-ls and having a couplermovable into and out of said pocket in response to buff and draft loads,respectively; a selective travel draft gear arrangement mounted in saidpocket and comprising a housing having front and rear chambers separatedby a fixed intermediate abutment wall in said housing, said front andrear chambers opening forwardly and rearwardly, respectively, saidhousing having a rear end terminating in forwardly spaced facingrelation to said stops and having a front end projecting forwardly fromsaid si-lls and providing an opening large enough to receive saidcoupler in said front chamber, said housing being mounted in said pocketfor movement in either lengthwise direction from a normal releaseposition, front and rear cushioning units in line in said housing onopposite regions of said intermediate wall, with adjacent ends of saidunits reacting against said intermediate wall, said housing and saidsills having first and second sets of slots aligned transversely of saidpocket, transverse stop key Vmeans projecting through said .sets ofslots and connecting said housing for limited lengthwise movementrela-tive to said sills, said housing and coupler having slots alignedtransversely of said pocket, transverse draft key means projectingthrough said sets of slots and connecting said coupler and housing, saidfront cushioning unit being operable in both buff and draft and being ofa positive resista-nce type having it-s forward end reacting againstsaid stop key means in draft and reacting against said coupler in buff,and said rear cushioning unit being operable only in buff and being aself-restoring hydraulic fluid throttling type that includes meansprojecting rearwardly from said housing and connected to transmit buffreaction to said stops.

5. In a railway car underframe of the type having fixed center sillscarrying fixed stops defining rear lateral extremities of draft pocketthat opens endwise forwardly from said sills and having a couplermovable into and out of said pocket in response to buff and draft loads,respectively; a selective travel draft gear arrangement mounted in saidpocket and comprising a housing having front and rear chambers separatedby a fixed intermediate abutment wall in said housing, said front andrear chambers opening forwardly and rearwardly, respectively, saidhousing having a rear end terminating in forwardly spaced facingrelation to said stops and having a front end projecting forwardly fromsills and providing an opening large enough to receive said coupler insaid front chamber, said housing being mounted in said pocket formovement in either lengthwise direction from a normal release position,front and rear cushioning units in line in said hou-sing on oppositeregions of said intermediate wall, with adjacent ends of said unitsreacting against said intermediate wall, said housing and said sillshaving first and second sets of slots aligned transversely of saidpocket, transverse stop key means projecting through said sets of slotsand connecting said housing for limited lengthwise movement relative tosaid sills, said housing and coupler having slots aligned transverselyof said pocket, transverse draft key means projecting into the lastnamed slots and connecting said coupler and housing, said frontcushioning unit being operable in both buff and draft and being of apositive resistance type having its forward end reacting .against saidstop key means in draft and reacting against said coupler in buff, andsaid rear vcushioning unit being a self-restoring hydraulic fluidthrottling type that includes rearwardly projecting means reactingagainst said stops to establish a release position for the draft geararrangement wherein said housing is biased forwardly to hold `the lirstnamed cushioning unit against said stop key means and provide clearancefor suicient rearward housing travel to enable a closure travel of saidrear cushioning unit in buff in an amount several '8 times greater thanclosure travel of the front cushioning unit in draft.

References Cited by the Examiner UNITED STATES PATENTS 2,889,056 6/1959Blattner 213-40 3,150,781 9/1964 Housman et al. 213--23 3,175,700 3/1965 Shirey 213-43 10 ARTHUR L. LA POINT, Primary Examiner.

1. IN COMBINATION WITH CAR UNDERFRAME STRUCTURE THAT INCLUDES LENGTHWISEEXTENDING FEXED SILLS DEFINING A DRAFT POCKET, A COUPLER PROJECTING INTOAND MOVABLE LENGTHWISE IN SAID POCKET, A BOLSTER CENTER FILLER BETWEENSAID SILLS AND HAVING RIGID STOPS BORDERING AND DEFINING REAR LATERALEXTREMITIES OF SAID POCKET, A SELECTIVE TRAVEL DRAFT GEAR COMBINATIONCOMPRISING A HOUSING PROJECTING FORWARDLY FROM SAID SILLS AND EXTENDINGLENGTHWISE REARWARDLY INTO SAID POCKET TO TERMINATE IN FORWARDLY SPACEDFACING RELATION TO SAID STOPS TO MOVE TOWARDS SAID STOPS IN BUFF, SAIDHOUSING HAVING A REAR CHAMBER OPENING TOWARDS SAID CENTER FILLER, AFRONT CHAMBER OPENING ENDWISE OPPOSITELY OF SAID REAR CHAMBER AND RIGIDINTERNAL ABUTMENT WALL STRUCTURE DIVIDING SAID CHAMBERS, A FOLLOWER INSAID POCKET TO ABUT SAID REAR STOPS, A CUSHIONING UNIT MOUNTED IN SAIDREAR CHAMBER TO OPERATE ONLY IN BUFF AND INCLUDING MEANS PROJECTINGREARWARDLY THEREFROM AND ENGAGED TO SAID FOLLOWER TO TRANSMIT BUFFREACTION TO SAID STOPS, SAID CUSHIONING UNIT BEING A SELF RESTORINGHYDRAULIC FLUID THROTTLING TYPE AND HAVING A COIL TYPE RETURN SPRINGENCIRCLING SAID MEANS AND REACTING BETWEEN SAID FOLLOWER